• Vaccine Name: live attenuated Brucella abortus strain 19 GFP vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0009230
• Type: Live attenuated vaccine
• Status: Research
• Host Species for Licensed Use: Cattle
• Host Species as Laboratory Animal Model: Mus musculus
• Antigen: green fluorescent protein (GFP)
• Preparation: The S19-GFP vaccine maintained all biochemical characteristics of the parental S19 vaccine and expressed GFP allowing identification under ultraviolet light. (Chacón-Díaz et al, 2011)
  Live attenuated Brucella abortus strain 19 genetically modified to express GFP; administered at 5×10^9 CFU by subcutaneous or conjunctival routes; some animals received a GFP boost seven weeks later. (Chacón-Díaz et al, 2021)
• Description: A prototype Brucella abortus strain 19 vaccine expressing green fluorescent protein (S19-GFP) was constructed to serve as a marker vaccine. Efficacy: S19-GFP protected mice against virulent Brucella abortus challenge to the same extent as the parental S19 vaccine. Immune response: Both S19-GFP and S19 vaccines induced similar levels of antibodies against lipopolysaccharide; anti-GFP antibodies allowed discrimination between S19-GFP vaccinated and S19 vaccinated mice. (Chacón-Díaz et al, 2011)
  The study developed a Brucella abortus strain 19 vaccine constitutively expressing green fluorescent protein (GFP) coded in chromosome II to allow serological differentiation of vaccinated cattle from infected animals. Efficacy: S19-GFP displayed similar biological characteristics and immunogenic and protective efficacies in mice compared to parental S19 strain; induced long-lasting anti-GFP antibodies in cattle, allowing differentiation from infected animals. Immune response: Vaccinated animals developed anti-S-LPS antibodies followed by anti-GFP antibodies; anti-GFP antibody response was higher in GFP-boosted animals; anti-GFP antibodies persisted as long or longer than anti-S-LPS antibodies, enabling serological identification of vaccinated cattle. (Chacón-Díaz et al, 2021)

Mouse Response

• Immune Response: Both S19-GFP and S19 vaccines induced similar levels of antibodies against lipopolysaccharide; anti-GFP antibodies allowed discrimination between S19-GFP vaccinated and S19 vaccinated mice. (Chacón-Díaz et al, 2011)
• Challenge Protocol: Replication was tested ex vivo and in vivo; protection was evaluated in mice challenged with virulent Brucella abortus; antibody responses were measured by immunoenzymatic assay. (Chacón-Díaz et al, 2011)
• Efficacy: S19-GFP protected mice against virulent Brucella abortus challenge to the same extent as the parental S19 vaccine. (Chacón-Díaz et al, 2011)
• Description: Replication was tested ex vivo and in vivo; protection was evaluated in mice challenged with virulent Brucella abortus; antibody responses were measured by immunoenzymatic assay. (Chacón-Díaz et al, 2011)